Modern communications devices may support a plurality of communications standards. For example, a “multi-mode” cellular phone may support a plurality of wireless cellular standards, including GSM and W-CDMA. Although the same circuitry may be shared among multiple modes, the requirements on the circuitry may be different depending on the mode and/or system planning. For example, operation in one mode may demand higher linearity from the transmit (TX) circuitry than operation in another mode. One parameter affecting the linearity of TX circuitry is the level of the voltage supply.
In typical multimode designs, the circuitry is supplied with the highest necessary voltage level for all modes of operation, potentially leading to inefficiently high power consumption for one or more of the modes. It would be desirable to dynamically adjust the voltage supplied to the circuitry or to selected blocks within the circuitry depending on the operating mode.